4RF E1, T1 Users Manual

Cross Connections | 134

QJET cross connections

Expand the E1 / T1 display by clicking on the relevant icons.

The QJET card can operate in several modes allowing you greater flexibility in tailoring or grooming traffic. The Data type selection are Off, E1, or T1 rates.

Note: An unframed E1 / T1 port requires 5 bits (or 40 kbit/s) of overhead traffic per port for synchronization.

An unframed E1 port with 2048 kbit/s of traffic requires 2088 kbit/s of link capacity. An unframed T1 port with 1544 kbit/s of traffic requires 1584 kbit/s of link capacity.

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For each port that you want to put into service, choose the required mode (either Unframed or Framed):

Unframed mode

Leave the Framed checkbox unticked.

Select the required Data type from the drop-down list E1 or T1.

Local drop and insert connections are not possible between Unframed E1 / T1 ports.

Framed mode

Tick the Framed checkbox.

Select the required framed mode from the drop-down list:

Local drop and insert connections are possible between framed E1 ports on the same interface card or E1 ports on different interface cards.

Local drop and insert connections are possible between framed T1 ports on the same interface card or T1 ports on different interface cards.

Local drop and insert connections are not possible between framed E1 ports and framed T1 ports.

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E1 Framed Modes

Framed Mode		Description
E1	– PCM 30	Provides 30 timeslots to transport traffic. Timeslot 16 carries channel
		associated signalling data (CAS).
E1	– PCM 31	Provides 31 timeslots to transport traffic. Timeslot 16 can be used for common
		channel signalling or to transport traffic.
E1	– PCM 30C	Same as E1 – PCM 30 mode but supports CRC-4.
E1	– PCM 31C	Same as E1 – PCM 31 mode but supports CRC-4.

E1 CRC-4 (cyclic redundancy check) is used to ensure correct frame alignment and also used to gather E1 performance statistics e.g. Errored Seconds (ES), Severely Errored Seconds (SES).

The first three bits of timeslot 0 NFAS (bits 0,1 & 2) and all of timeslot 0 FAS are not transported across the link, but rather terminated and regenerated at each terminal.

The last five bits of timeslot 0 NFAS (bits 3 – 7) are the National Use Bits (NUBs) which can be cross connected locally or over the link.

E1 - PCM 30 mode

E1 - PCM 30 modes are used when access to the signalling bits (ABCD) is required, for example:

Splitting a PCM 30 E1 into two separate PCM 30 E1s

Cross connecting signalling from DFXS, DFXO or Q4EM interfaces into an PCM 30 E1

Drop and Insert connections between PCM 30 E1s

In PCM 30 / PCM 30C mode, the timeslot table left column is used to map timeslot bits and the timeslot table right column is used to map CAS bits (ABCD) for signalling. Timeslot 16 is reserved to transport the CAS multi frame.

One use of this mode is to connect the 4 wire E&M interfaces to third-party multiplexer equipment over the E1 interface using CAS in TS16 to transport the E&M signalling.

To configure this mode correctly, you must have a detailed knowledge of the CAS signalling modes for the third-party equipment to ensure the signalling bits are compatible and configured to interoperate.

E1 - PCM 31 mode

E1 - PCM 31 modes are used to cross connect timeslots bits without the signalling bits (ABCD).

TS16 can be cross connected between E1 ports (to transport the entire CAS multi frame) or used for common channel signalling or to transport traffic.

The timeslot table left column is used to map timeslot bits but the timeslot table right column for CAS bits (ABCD) is not used.

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T1 Framed Modes

Framed Mode		Description
T1	- SF	Provides 24 timeslots to transport traffic using the G.704 12 frame Super
		Frame without signalling. There is no CRC capability with the SF.
T1	– SF 4	Provides 24 timeslots to transport traffic using the G.704 12 frame Super
		Frame with 4 state signalling (AB bits). There is no CRC capability with the SF.
T1	– ESF	Provides 24 timeslots to transport traffic using the G.704 24 frame Extended
		Super Frame with CRC and without signalling.
T1	– ESF 4	Provides 24 timeslots to transport traffic using the G.704 24 frame Extended
		Super Frame with CRC and 4 state signalling (AB bits).
T1	– ESF 16	Provides 24 timeslots to transport traffic using the G.704 24 frame Extended
		Super Frame with CRC and 16 state signalling (ABCD bits).

For the 24 framed modes of ESF 4 and ESF 16, the Data Link bit is shown in the timeslot table but is currently unavailable for use.

T1 - SF mode

T1 SF mode provides 24 timeslots to transport traffic using the G.704 12 frame Super Frame without demultiplexing the signalling. Complete timeslots can be cross connected including the inherent robbed signalling bits.

The timeslot table left column is used to map timeslot bits but the timeslot table right column for CAS bits (ABCD) is not used.

T1 SF mode is used when access to the signalling bits is not required but are transported between T1s, for example:

Drop and Insert connections between 12 frame Super Frame T1s or data interfaces

T1 - SF 4 mode

T1 SF 4 mode provides 24 timeslots to transport traffic using the G.704 12 frame Super Frame with four state demultiplexed signalling using the AB bits.

The mapping left column is used to map timeslot bits and the timeslot table right column is used to map the CAS A&B bits for signalling (C&D bits are not used).

T1 SF mode is used when access to the signalling bits is required, for example:

Cross connecting signalling from DFXS, DFXO or Q4EM interfaces into a 12 frame Super Framed T1 using ‘multiplexed’ signalling from the interface.

Drop and Insert connections between 12 frame Super Framed T1s or data interfaces

T1 - ESF mode

T1 ESF mode provides 24 timeslots to transport traffic using the G.704 12 frame Extended Super Frame without demultiplexing the signalling. Complete timeslots can be cross connected including the inherent robbed signalling bits.

The timeslot table left column is used to map timeslot bits but the timeslot table right column for CAS bits (ABCD) is not used.

T1 ESF mode is used when access to the signalling bits is not required but are transported between T1s, for example:

Drop and Insert connections between 24 frame Extended Super Framed T1s or data interfaces

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T1 - ESF 4 mode

T1 ESF 4 mode provides 24 timeslots to transport traffic using the G.704 24 frame Extended Super Frame with four state demultiplexed signalling using the AB bits each with a bit rate of 667 bit/s.

The mapping left column is used to map timeslot bits and the timeslot table right column is used to map the CAS A&B bits for signalling (C&D bits are not used).

T1 ESF 4 mode is used when access to the signalling bits is required, for example:

Cross connecting signalling from DFXS, DFXO or Q4EM interfaces into a 24 frame Extended Super Framed T1 using ‘multiplexed’ signalling from the interface.

Drop and Insert connections between 24 frame Extended Super Framed T1s or data interfaces

T1 - ESF 16 mode

T1 ESF 16 mode provides 24 timeslots to transport traffic using the G.704 24 frame Extended Super Frame with sixteen state demultiplexed signalling using the ABCD bits each with a bit rate of 333 bit/s.

The mapping left column is used to map timeslot bits and the timeslot table right column is used to map the CAS ABCD bits for signalling.

T1 ESF 16 mode is used when access to the signalling bits is required, for example:

Cross connecting signalling from DFXS, DFXO or Q4EM interfaces into a 24 frame Extended Super Framed T1 using ‘non-multiplexed’ signalling from the interface.

Drop and Insert connections between 24 frame Extended Super Framed T1s or data interfaces

Cross Connections | 139

Selecting and mapping bits and timeslots

This section describes how to select and map:

a single bit

multiple bits

a 64 kbit/s timeslot

multiple timeslots

Selecting a single bit

Each timeslot is represented by 8 rectangles (each representing a single bit). Each bit can carry 8 kbit/s.

One or more consecutive bits can be selected in a timeslot if a rate of greater than 8 kbit/s is required.

1. Click on the rectangle that represents the bit you require. It will turn red.

2. Click and drag this bit to the rectangle representing the bit on the interface you want it to be connected to, and release the mouse button.

The red rectangle will be replaced by the allocated connection number at each interface.

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Selecting multiple bits

It is possible to select multiple consecutive bits if circuit capacity of greater than 8 kbit/s is required.

1. Click the first bit, and then hold down the Ctrl key while selecting the remaining bits.

2. Click and drag the whole block by clicking the bit on the left hand side of your selection, and drag to the required interface. Release the mouse button.

Tip: It is also possible to select multiple bits by holding down the Shift key, and dragging across the required rectangles.

Differing numbers of bits display in different colors when the cross-connect is completed:

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Selecting a 64 kbit/s timeslot

1. Click on the TSX timeslot number (where X is the desired timeslot from 1 to 31).

Alternatively, right-click over any of the bits in the timeslot, and click on Select Timeslot.

2. Drag and drop in the normal way to complete the cross connection.

Selecting multiple non consecutive timeslots

1.Click on one TSn timeslot number (where n is the desired timeslot 1 to 31).

2.Hold down the Ctrl key while clicking on each of the required timeslot numbers.

3. Drag and drop in the normal way to complete the cross connection.

Cross Connections | 142

Selecting multiple consecutive timeslots

1.Click on the first TSn timeslot number (where n is the desired timeslot 1 to 31).

2.Hold down the Shift key while clicking on the last required timeslot number.

3. Drag and drop in the normal way to complete the cross connection.

Selecting all timeslots in a port

1. Right-click over any of the rectangles.

2. Click Select All.

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Q4EM cross connections

1. Expand the Q4EM display by clicking the relevant icon.

2.Set the Voice capacity by selecting 16, 24, 32, or 64 kbit/s rates.

3.Drag and drop from the Voice mapping connection box to the required partner interface to create the voice cross connection.

4.If E&M signalling is required, drag and drop from the Signalling mapping connection box to the required partner interface to create the E&M cross connection.

Cross Connections | 144

DFXS & DFXO cross connections

1. On one side of the link, expand the DFXS display, as required, by clicking .

2. On the other side of the link, expand the corresponding DFXO display, as required, by clicking .

3. For the DFXS card and corresponding DFXO card, select the Signalling type as required, according to the table below. The CAS signalling between DFXO / DFXS interfaces uses 4RF proprietary allocation of control bits.

The Signalling type affects both ports of the DFXO / DFXS interface. If a mixture of signalling types is required, then multiple DFXO / DFXS cards are needed.

Signalling	Application	Overhead
Multiplexed	Multiplexers the four ABCD bits from the interface into a	8 kbit/s
(default)	single 8 kbit/s channel.
	Use when interworking DFXO to DFXS, between an XE
	and a SE radio or when limited bandwidth is available.
	This signalling type cannot be used for interworking
	between framed E1 and voice interfaces.
Non-multiplexed	Transports each of the four ABCD bits in separate 8 kbit/s	32 kbit/s
	channels.
	Use when interworking DFXO cards to DFXS cards or
	when signalling bits are mapped into an E1 / T1 timeslot.
4 wire compatible	Use when interworking the DFXO card or DFXS card to a	8 kbit/s
	Q4EM interface
	• DFXS to DFXO A bit mapped to off-hook
	• DFXO to DFXS A bit mapped to fault

4.Set the Voice capacity and create the Voice connection by dragging and dropping between the mapping connection boxes of the DFXO and DFXS corresponding ports.

5.Link the Port Signalling connection by dragging and dropping between the mapping connection boxes of the DFXO and DFXS corresponding ports. The DFXO / DFXS control signals (off hook, ring, etc) will not function without this connection.

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QV24 cross connections

1. Expand the QV24 displays, as required, by clicking the relevant icons.

2.Select the Port Baud Rate as required (default is 9600).

3.Drag and drop to the required partner interface to create the V.24 Data connection. If the partner interface is a QJET:

If the V.24 Baud Rate selected is 38400 is less, drag from the QV24 mapping connection box to the QJET timeslot. The correct QJET capacity for the baud rate selected will automatically be assigned.

If the V.24 Baud Rate selected is greater than 38400, select the QJET capacity required, as per the following table, and drag from the QJET to the QV24 mapping connection box.

Baud Rate		Bits Required	Bit Rate
300	- 7200	2	16 kbit/s
9600	- 14400	3	24 kbit/s
19200 - 23040		4	32 kbit/s
28800		5	40 kbit/s
38400		6	48 kbit/s
57600		9	72 kbit/s
115200		16	128 kbit/s

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HSS cross connections

1. Expand the HSS displays, as required, by clicking the relevant icons.

2. Select the Synchronous Clock Selection mode (see “HSS synchronous clock selection modes” on page 114).

3.Set the Data rate to a value between 8 and 2048 (in multiples of 8 kbit/s). The net data rate available to the user is defined by Data Rate – overhead

e.g. a date rate set to 2048 kbit/s with an overhead of 40 kbit/s provides a user data rate of 2008 kbit/s

4.Drag and drop to the required partner interface to create the HSS Data connection.

If the partner interface is a QJET, select the capacity on the QJET and drag it to the HSS Data mapping connection box.

The QJET capacity selected must be the sum of the data rate required plus the overhead rate selected.

5.Drag and drop to the required partner interface to create the HSS Signalling cross connection. A minimum of 8 kbit/s of capacity is required and must be set symmetrically at both ends of the link.

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Cross connection example

This is an example of cross connection mapping:

Circuit	Local port	Remote port	Capacity	Connection
			(kbit/s)	numbers
Radio management			64	1
User Ethernet			1024	2
3 wire E&M circuit	Q4EM port 1	Q4EM port 1	72	7/15
	(slot C)	(slot C)
Unframed E1 data	QJET port 1	QJET port 1	2088	65
	(slot D)	(slot D)
Unframed T1 data	QJET port 2	QJET port 2	1584	66
	(slot D)	(slot D)
Loop Interface	DFXO port 1	DFXS port 1	72	8/32
	(slot E)	(slot E)
V.24 data circuit	QV24 port 1	QV24 port 1	24	14
9600	(slot G)	(slot G)
HSS data circuit	HSS port 1	HSS port 1	1088	31/16
1024 kbit/s	(slot H)	(slot H)

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Symmetrical Connection Wizard

The Cross Connections application has a Symmetrical Connection Wizard which simplifies the cross connection configuration when the terminals are fitted with symmetrical / matching interface types.

A symmetrical connection is a connection between the local and the remote terminal where the local slot, card type, port and connection details are identical to those of the remote terminal.

The only exception is DFXO / DFXS connections where DFXO cards are considered to match DFXS cards (as they normally interwork).

Framed E1 / T1 CAS connections, drop-and-insert connections, and connections that do not involve entire timeslots, are considered to be asymmetrical.

Starting the wizard

When starting the wizard with unsaved changes, the following popup dialog should appear

Click on 'Save' if you wish to save the current configuration to a file. Clicking on 'Continue' will continue with the wizard and overwrite any changes made when the wizard finishes.

The wizard can be cancelled at any time by clicking on the 'Cancel' button or by closing the window.

Wizard Navigation

Click on the Next button to progress through the wizard. The current stage is indicated in the navigation bar on the left. You can jump directly to a stage by clicking on the stage required.

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Setting the IP address

If the local or remote terminal IP addresses have been setup, they will be displayed in the Local and Remote fields. If the IP addresses are not displayed, enter the IP addresses of the local and remote terminals.

Click on 'Get Configuration' to upload the existing cross connections configuration from the local terminal. The Radio bandwidth bar will show the available bandwidth and will be updated as bandwidth is assigned to cards.

Setting the bandwidth

If the Cross Connections Application is opened from SuperVisor, the Total Capacity of the radio link will be shown in the Bandwidth field.

If the Cross Connections Application is opened as a stand alone application, the Total Capacity of the radio link will be need to be entered in the Bandwidth field.

The 'Remove asymmetrical connections' button will be active if there are existing asymmetrical cross connections. If you want to remove existing asymmetrical cross connections, click on this button. The Radio bandwidth bar will update accordingly.

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Card Selection

If the Cross Connections Application is opened from SuperVisor, existing cards installed in the local terminal that match cards installed in the remote terminal will be displayed. Mismatched cards will be shown as 'Empty Slot'.

If the Cross Connections Application is opened as a stand alone application, select the card types that will be fitted in the terminal.

To copy the card type selected in Slot A to all the other slots (B – H), click on the Copy Card button. This assumes that the same interface card types are fitted in all the card slots.

Cross Connections | 151

Interface configurations

Setup the interface configurations as per the wizard instructions. Existing asymmetrical connections will be replaced with symmetrical connections if an interface parameter is changed.

Q4EM

QJET

DFXO / DFXS

QV24

HSS

Ethernet

To copy the port configuration selected in Port 1 to all the other ports on the card, click on the Copy Port button.

To copy the card configuration to all other cards of the same type fitted in the terminal, click on the Copy Card button. This can save time when setting up multiple cards of the same type.

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Symmetrical connection summary

Click Finish.

Send symmetrical connection configuration

Click OK to send the configuration to the terminals.

The process is completed.

Note: The wizard may change the connection numbers of existing connections.

Protected terminals | 153

11. Protected terminals

Monitored Hot Stand By (MHSB)

This section describes configuring the protected terminal in MHSB mode. A protected terminal in MHSB mode comprises two radios interconnected using the tributary and RF switches as shown below:

The MHSB switch protects terminals against any single failure in one radio. It also monitors the alarm output of each radio and switches between radios if major radio link alarms occur.

The MHSB switch uses a CPU to monitor the alarm status received from both the connected radios' alarm ports. When a relevant major radio link alarm is detected on the active radio (that is, transmitter, receiver, power supply or modem), the CPU switches a bank of relays that switches all the interfaces and the transmit port from the main radio to a functioning stand-by radio. The stand-by radio now becomes the active radio.

The tributary switch and the RF switch are both a 19-inch rack-mount 1U high chassis. The total rack space required is 6U. The MHSB switch option is available for the following bands: 300, 400, 700, 900, 1400, 2000, and 2500 MHz.

Protected terminals | 154

Tributary switch front panel

No.	Description	Explanation
1	Power supply input	Input for DC power or AC power
2	Protective earth	M5 terminal intended for connection to an external protective
		conductor for protection against electric shock in case of a fault
3	Interface ports	Port for connecting to customer interface equipment
4	Radio A interfaces	These connect to the interface ports on radio A
5	Radio B interfaces	These connect to the interface ports on radio B
6	Console	For factory use only
7	Ethernet	Port for connecting to customer Ethernet network. This port is also
		used to set up and manage the radios remotely over an IP
		network
8	Radio A Ethernet	Connects to an Ethernet port on radio A
9	Radio B Ethernet	Connects to an Ethernet port on radio B
10	Alarms	Alarm input/output connections for customer equipment
11	Radio A alarms	Connects to the alarm port on radio A
12	Radio B alarms	Connects to the alarm port on radio B
13	RF SW	Provides power and signalling to the RF switch
14	Mode switch	Three-position locking toggle switch to set the MHSB switch into
		automatic mode or radio A / radio B test mode
15	LEDs	Mode and status LEDs

			Protected terminals | 155
Tributary protection switch LEDs
LED	Colour	Appearance	Explanation
A	Green	Solid	The radio is active and is OK
	Green	Flashing	The radio is in standby mode and is OK
	Red	Solid	The radio is active and there is a fault
	No colour (off)	-	The tributary switch is in 'slave' mode and the
			switching is controlled by the master tributary
			switch
	Red	Flashing	The radio is in standby mode, and there is a fault
B	Green	Solid	The radio is active and is OK
	Green	Flashing	The radio is in standby mode and is OK
	Red	Solid	The radio is active and there is a fault
	No colour (off)	-	The tributary switch is in 'slave' mode and the
			switching is controlled by the master tributary
			switch
	Red	Flashing	The radio is in standby mode, and there is a fault
~	Green	Solid	The tributary protection switch is in 'auto' mode
	Green	Flashing	The tributary protection switch is in 'slave' mode
	Red	Solid	The tributary protection switch is in 'manual' mode
			(A or B)
On	Blue	Solid	Indicates that there is power to the tributary
			protection switch

RF switch front panel

No.	Description	Explanation
1	Radio QMA	QMA connectors for connecting the protected radios
2	Protective earth	M5 terminal intended for connection to an external protective
		conductor for protection against electric shock in case of a fault
3	Antenna port	N-type female connector for connection to the antenna feeder
		cable. This view shows an internally mounted duplexer. If an
		external duplexer is fitted, the antenna port will be on the external
		duplexer
4	Slave tributary switch	Connects to secondary tributary switch for control of additional
	outputs	interfaces
5	Tributary switch	Connects the RF switch to the tributary switch (the master if more
		than one tributary switch is required)
6	LEDs	Status LEDs

			Protected terminals | 156
RF protection switch LEDs
LED	Colour	Appearance	Explanation
Tx A	Green	Solid	RF is being received from radio A
Tx B	Green	Solid	RF is being received from radio B
On	Blue	Solid	Indicates that there is power to the RF protection switch

Slave tributary switches

Each tributary switch protects up to eight ports. Up to three slave tributary switches may be added to a MHSB terminal to protect up to 32 ports. Each slave tributary switch is interconnected by means of the slave tributary switch ports on the RF switch, as shown below.

Note: A tributary switch that is operating as a slave (rather than a master) has a RJ-45 V.24 loopback connector plugged into the console port. If the connector is missing, contact Customer Support. Alternatively, you can make this connector. Follow the standard pinouts for a V.24 RJ-45 connection (see "QV24 Interface connections" on page 228).

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MHSB cabling

The two radios are interconnected as follows:

Caution: Do not connect Transmit to Receive or Receive to Transmit as this may damage the radio or the MHSB switch.

Cables supplied with MHSB

The following cables are supplied with a MHSB terminal:

Ethernet interface: RJ-45 ports standard TIA-568A patch cables .

Alarm interface: RJ-45 ports standard TIA-568A patch cables.

RF ports: two QMA male patch cables are supplied.

MHSB power supply

See “DC power supply” on page 32 and “AC power supply” on page 35.

Protected terminals | 158

Configuring the radios for protected mode

The MHSB switch does not require any special software. However, the radios connected to the MHSB switch must be configured to work with the MHSB switch. This sets the alarm outputs and inputs to function in MHSB mode.

You must configure the interfaces of both radios connected to the MHSB switch identically. To perform this, you can either connect directly to the radio or use the test mode of the MHSB switch.

IP address setup

Before configuring the link, you must ensure that the two independent links have correctly configured IP address details.

All four radios in the protected link must be on the same subnet.

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Mounting the MHSB radios and switch

Once the IP addresses are correctly configured, it is important to connect the A and B radios' Ethernet and Alarm ports correctly. In general, mount radio A above the MHSB switch and radio B below the MHSB switch:

There is an Ethernet connection between any of the four Ethernet ports on each radio and the Ethernet port on the Tributary switch. There is also a connection between radio A and radio B, which ensures Ethernet traffic is maintained if a radio loses power.

The Ethernet port on the protection switch can be connected to an Ethernet hub or switch to allow multiple connections.

Important: The management Ethernet capacity on each of the four radios in the protected terminal must be identical for remote communications to work and there should only be one IP connection to the management network (via the tributary switch Ethernet port).

Protected terminals | 160

Configuring the terminals for MHSB

It is recommended that you configure the local and remote A side first, then the local and remote B side. Both the local A and B radios must be configured identically, and both the remote A and B radios must be configured identically.

Tip: As illustrated below, you may find it helpful to have two browser sessions running simultaneously. You can then easily see both the A and B sides of the protected link.

To configure MHSB operation:

1. Select Link > Maintenance > MHSB.

2.Enable MHSB mode.

3.Select whether the radio is A or B.

Ensure that the radio connected to the A side of the protection switch (normally above the MHSB switch) is set to Radio A and the radio connected to the B side of the protection switch (normally below the MHSB switch) is set to Radio B.

In the event of a power outage, the radios will switch over to the A side of the protection switch when the power is restored. The A side is also the default active side.

4.When you have made your changes, click Apply to apply changes or Reset to restore the previous configuration.

5.Repeat steps 2 to 4 for the other side of the protected link.

Protected terminals | 161

Clearing MHSB alarms

If a switchover event occurs, the OK LED on the front panel and on the Terminal status and menu bar in SuperVisor changes to orange.

1. Select Clear Switched Alarm from the MHSB Command drop-down list.

2. Click Apply to apply changes or Reset to reset the page.

Note: When MHSB mode is enabled, external alarm input 2 is used by the protection system to carry alarms from the protection switch to the radio. In MHSB mode, therefore, only external alarm input 1 is available for user alarms.

In-service commissioning | 163

12. In-service commissioning

Before you start

When you have finished installing the hardware, RF and the traffic interface cabling, the system is ready to be commissioned. Commissioning the terminal is a simple process and consists of:

1.Powering up the terminals

2.Configuring both the local and remote terminals using SuperVisor

3.Aligning the antennas

4.Synchronizing the terminals

5.Testing the link is operating correctly. As a minimum, conduct the suggested tests to ensure correct operation. More extensive testing may be required to satisfy the end client or regulatory body requirements.

6.Connecting up the client or user interfaces

What you will need

Appropriately qualified commissioning staff at both ends of the link.

Safety equipment appropriate for the antenna location at both ends of the link.

Communication equipment, that is, mobile phones or two-way radios.

SuperVisor software running on an appropriate laptop, computer, or workstation at one end of the link.

Tools to facilitate loosening and re-tightening the antenna pan and tilt adjusters.

Predicted receiver input levels and fade margin figures from the radio link budget (You can use Surveyor (see "Path planning" on page 19) to calculate the RSSI, fade margin, and availability).

In-service commissioning | 164

Applying power to the terminals

Caution:

Before applying power to a terminal, ensure you have connected the safety earth and antenna cable.

Apply power to the terminals at each end of the link.

When power is first applied, all the front panel LEDs will illuminate red for several seconds as the system initializes.

After the system is initialized, the OK LED on the front panel should illuminate green and if the terminals are correctly configured, the TX and RX LED should also be illuminated green.

If the RX LED is:

Red — the antennas are may be significantly mis-aligned with no signal being received.

Orange — the antennas may be roughly aligned with some signal being received.

Green — the antennas are well-aligned and adequate signal is being received to create a reliable path.

If the TX LED is:

Red — there is a fault in the antenna or feeder cable, or the transmitter is faulty.

Green — this means the transmitter is working normally.

Review the link configurations using SuperVisor

1.Connect a PC, with SuperVisor installed, to both terminals in the link.

2.Log into the link.

3.Select Link > Summary and confirm the following basic information:

Terminal IP address(es)

Terminal TX and RX frequencies

RSSI (dBm)

TX power (dBm)

SNR (dBm)

Note: If the terminals have not already been configured, refer to "Configuring the terminal" on page 61, "Configuring the traffic interfaces" on page 77, and "Configuring the traffic cross connections" on page 121.

In-service commissioning | 165

Antenna alignment

For any point-to-point link, it is important to correctly align the antennas to maximize the signal strength at both ends of the link. Each antenna must be pointing directly at the corresponding antenna at the remote site, and they must both be on the same polarization. The antennas are aligned visually, and then small adjustments are made while the link is operating to maximize the received signal.

Directional antennas have a radiation pattern that is most sensitive in front of the antenna, in line with the main lobe of the radiation pattern. There are several other lobes (side lobes) that are not as sensitive as the main lobe in front of the antenna.

For the link to operate reliably, it is important that the main lobes of both antennas are aligned. If any of the side lobes are aligned to the opposite antenna, the received signal strength of both terminals will be lower, which could result in fading. If in doubt, check the radiation patterns of the antennas you are using.

Checking the antenna polarization

Check that the polarization of the antennas at each end of the link is the same.

Antenna polarization of grid antennas are normally indicated by an arrow or with “H” and “V” markers (indicating horizontal and vertical).

On Yagi antennas, ensure the orientation of the elements are the same at each end of the link.

Transmit frequency and power, and antenna polarization would normally be defined by a regulatory body, and typically licensed to a particular user. Refer to your license details when setting the antenna polarization.

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Visually aligning antennas

1. Stand behind the antenna, and move it from side to side until it is pointing directly at the antenna at the remote site. The remote antenna may be made more visible by using a mirror, strobe light, or flag.

If the remote end of the link is not visible (due to smoke, haze, or local clutter, etc), align the antenna by using a magnetic compass. Calculate the bearing using a scale map of the link path.

When setting the antenna on the desired bearing ensure that you use the appropriate true-north to magnetic-north offset. Also ensure that the compass reading is not affected by standing too close to metallic objects.

2.Once the antenna is pointing at the remote antenna, tighten the nuts on the U-bolt or antenna clamp just enough to hold it in position. Leave the nuts loose enough so that small adjustments can still be made. Check that the antenna is still pointing in the correct direction.

3.Move the antenna up or down until it is pointing directly at the remote site.

4.Tighten the elevation and azimuth adjustment clamps.

5.Mark the position of the antenna clamps so that the antenna can be returned to this rough aim point easily when accurately aligning the antennas.

6.Repeat steps 1-5 at the opposite site.

Note: Low gain antennas need less adjustment in elevation as they are simply aimed at the horizon. They should always be panned horizontally to find the peak signal.

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Accurately aligning the antennas

Once the antennas are visually aligned, accurately align both antennas by carefully making small adjustments while monitoring the RSSI. This will give the best possible link performance.

Note: Remember that it is important to align the main radiation lobes of the two antennas to each other, not any side lobes. It may be easier to perform this procedure if you can communicate with someone at the remote site by telephone, mobile, or two-way radio.

1.Connect a laptop PC running SuperVisor software and power up the terminals at both ends of the link. Select Link > Performance > Summary so that you can see the RSSI indication for the local terminal. Alternatively, use the RSSI test point on the front panel together with a multimeter (see "Measuring6 the RSSI” on page 168).

2.Move the antenna through a complete sweep horizontally (known as a 'pan') either side of the point established in the visual alignment process above. Note down the RSSI reading for all the peaks in RSSI that you discover in the pan.

3.Move the antenna to the position corresponding to the maximum RSSI value obtained during the pan. Move the antenna horizontally slightly to each side of this maximum to find the two points where the RSSI drops slightly.

4.Move the antenna halfway between these two points and tighten the clamp.

5.If the antenna has an elevation adjustment, move the antenna through a complete sweep (known as a 'tilt') vertically either side of the point established in the visual alignment process above. Note down the RSSI reading for all the peaks in RSSI that you discover in the tilt.

6.Move the antenna to the position corresponding to the maximum RSSI value obtained during the tilt. Move the antenna slightly up and then down from the maximum to find the two points where the RSSI drops slightly.

7.Move the antenna halfway between these two points and tighten the clamp.

8.Recheck the pan (steps 2-4) and tighten all the clamps firmly.

9. Perform steps 1-8 at the remote site.

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Measuring the RSSI

Measure the RSSI value with a multimeter connected to the RSSI test port on the front of the terminal (see "Front panel connections and indicators" on page 27).

1.Insert the positive probe of the multimeter into the RSSI test port, and clip the negative probe to the chassis of the terminal (earth).

2.Pan and tilt the antenna until you get the highest VDC reading. The values shown in the table below relate the measured VDC to the actual received signal level in dBm regardless of bandwidth and frequency.

RSSI test	RSSI		RSSI test	RSSI		RSSI test	RSSI
port value	reading		port value	reading		port value	reading
(VDC)	(dBm)		(VDC)	(dBm)		(VDC)	(dBm)
0.000	- 100		0.675	- 73		1.350	- 46
0.025	- 99		0.700	- 72		1.375	- 45
0.050	- 98		0.725	- 71		1.400	- 44
0.075	- 97		0.750	- 70		1.425	- 43
0.100	- 96		0.775	- 69		1.450	- 42
0.125	- 95		0.800	- 68		1.475	- 41
0.150	- 94		0.825	- 67		1.500	- 40
0.175	- 93		0.850	- 66		1.525	- 39
0.200	- 92		0.875	- 65		1.550	- 38
0.225	- 91		0.900	- 64		1.575	- 37
0.250	- 90		0.925	- 63		1.600	- 36
0.275	- 89		0.950	- 62		1.625	- 35
0.300	- 88		0.975	- 61		1.650	- 34
0.325	- 87		1.000	- 60		1.675	- 33
0.350	- 86		1.025	- 59		1.700	- 32
0.375	- 85		1.050	- 58		1.725	- 31
0.400	- 84		1.075	- 57		1.750	- 30
0.425	- 83		1.100	- 56		1.775	- 29
0.450	- 82		1.125	- 55		1.800	- 28
0.475	- 81		1.150	- 54		1.825	- 27
0.500	- 80		1.175	- 53		1.850	- 26
0.525	- 79		1.200	- 52		1.875	- 25
0.550	- 78		1.225	- 51		1.900	- 24
0.575	- 77		1.250	- 50		1.925	- 23
0.600	- 76		1.275	- 49		1.950	- 22
0.625	- 75		1.300	- 48		1.975	- 21
0.650	- 74		1.325	- 47		2.000	- 20

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Synchronizing the terminals

After you have completed the alignment of the two antennas, you must ensure the two terminals are synchronized.

The terminals are synchronized when:

the OK LED is green, which indicates that no system alarms are present, and

the RX LED is green, which indicates a good signal with no errors, and

the TX LED is green, which indicates that there are no transmitter fault conditions.

Checking performance

The amount of testing performed on the completed installation will depend on circumstances. Some customers may need to prove to a local licensing regulatory body that the link complies with the license provisions. This may require special telecommunications test equipment to complete these tests. Most customers simply want to confirm that their data traffic is successfully passing over the link, or that the customer interfaces comply with known quality standard.

However, the most important performance verification checks are:

Receive input level

Fade margin

Long-term BER

Checking the receive input level

The received signal strength at the local terminal is affected by many components in the system and has a direct relationship with the resulting performance of the link. A link operating with a lower than expected signal strength is more likely to suffer from degraded performance during fading conditions. The receive input level of a link is normally symmetrical (that is, similar at both ends).

1.Compare the final RSSI figure obtained after antenna alignment with that calculated for the link.

2.If the RSSI figure is in excess of 3 dB down on the predicted level, recheck and correct problems using the table below and then recheck the RSSI. Alternatively, recheck the link budget calculations.

Possible cause	Terminal(s)
Is the terminal operating on the correct frequency?	Local & remote
Is the remote terminal transmit power correct?	Remote
Are all the coaxial connectors tight?	Local & remote
Is the antenna the correct type, that is, gain and frequency of operation?	Local & remote
Is the antenna polarized?	Local & remote
Is the antenna aligned?	Local & remote
Is the path between the terminals obstructed?

Note: If following the above steps does not resolve the situation, contact Customer Support for assistance.

3.Record the RSSI figure on the commissioning form.

4.Repeat steps 1 to 2 for the other end of the link.

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Checking the fade margin

The fade margin is affected by many components in the system and is closely related to the received signal strength. A link operating with a lower than expected fade margin is more likely to suffer from degraded performance during fading conditions. A reduced fade margin can be due to operating the link too close to the noise floor, or the presence of external interference. The fade margin of a link can be asymmetrical (that is, different at each end).

Possible causes of low fade margin are as follows:

Problem	Terminal
Low receive signal strength (see above table)	Local and Remote
Interfering signals on the same, or very close to, the frequency of the	Local
local terminal receiver.
Intermodulation products that land on the same or very close to the	Local or Remote
frequency of the local terminal receiver.
Operating near the local receiver noise floor	Local

To check the fade margin:

1. Confirm (and correct if necessary) the receive input level (see the previous test).

Note: If the receive input level is lower than expected, the fade margin may also be low.

2.Select Link > Performance > Summary and check the current BER of the link in its normal condition is better than 10-6 (If necessary, clear out any extraneous errors by clicking Reset Counters).

3.Check the signal to noise (S/N) indication on the Link > Performance > Summary page. This shows the quality of the signal as it is being processed in the modem. It should typically be better than 30 dB. If it is less than 25 dB, it means that either the RSSI is very low or in-band interference is degrading the S/N performance.

4.Temporarily reduce the remote site's transmit power using either an external attenuator or SuperVisor (Remote > Terminal > Basic).

Note: Ideally, the transmit power of the remote site should be reduced by up to 20 dB, which will require the use of an external 50 ohm coaxial attenuator capable of handling the transmit power involved. In the absence of an attenuator, reduce the transmit power using SuperVisor.

5.Check and note the current BER of the link in its now faded condition (Again, if necessary, clear out any extraneous errors (introduced by the power reduction step above) by clicking Reset Counters).

6.Compare the unfaded and faded BER performance of the link (steps 2 and 4). Continue to reduce the remote transmit power until either the BER drops to 10-6 or the remote transmitter power has been reduced by 20 dB.

Note: The fade margin of the link is expressed as a number (of dB) that the link can be faded (transmitter power reduced) without reducing the BER below operating specifications (1 * 10-6 BER). A 20 dB fade margin is adequate for most links.

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7. Record the fade margin and SNR results on the commissioning form.

Note: If the transmit power is reduced using SuperVisor rather than an external attenuator, the fade margin should be recorded as “Greater than x dB” (where x = the power reduction).

8.Restore the remote terminal transmit power to normal.

9.Repeat steps 1 to 7 for the other end of the link.

Note: If following all the guidelines above does not resolve the situation, contact Customer Support for assistance.

Checking long-term BER

The BER test is a measure of the stability of the complete link. The BER results of a link can be asymmetrical (that is, different at each end).

1.Select Link > Performance > Summary and check the current BER and error counters of the link. (If necessary, clear out any extraneous errors by selecting Reset Counters).

2.Wait 15 minutes, and check the BER display and error counters again. If there are a small number of errors and the BER is still better than 10-9, continue the test for 24 hours. If there are a significant number of errors, rectify the cause before completing the 24 hour test.

Note: It is normal to conduct the BER test in both directions at the same time, and it is important that no further work be carried out on the equipment (including the antenna) during this period.

3.The BER after the 24 hour test should typically be better than 10-8.

4.Record the BER results on the commissioning form.

Bit Error Rate tests

A Bit Error Rate (BER) test can be conducted on the bench, (see “Bench setup” on page 37).

Attach the BER tester to the interface port(s) of one terminal, and either another BER tester or a loopback plug to the corresponding interface port of the other terminal.

This BER test can be carried out over the Ethernet, E1/T1, V.24 or HSS interfaces. It will test the link quality with regard to user payload data.

Caution: Do not apply signals greater than -20 dBm to the antenna as they can damage the receiver. In a bench setup, there must be 60 - 80 dB at up to 2 GHz of 50 ohm coaxial attenuation (capable of handling the transmit power) between the terminals’ antenna connectors.

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Additional tests

Depending on license requirements or your particular needs, you may need to carry out additional tests, such as those listed below.

Refer to the relevant test equipment manuals for test details.

Test	Test equipment required
TX power output measurements (at TX and	Power meter
duplexer outputs)
TX spectrum bandwidth	Spectrum analyzer
TX spectral purity or harmonic outputs	Spectrum analyzer
TX center frequency	Frequency counter or spectrum analyzer
Bulk capacity BER test	BER tester
LAN throughput or errors	LAN tester
G.703 / HDB3 waveforms	Digital oscilloscope
Serial interface BER	BER tester
Audio quality	PCM4 or SINAD test set

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Checking the link performance

For a graphical indication of the link performance, you can use the constellation analyzer.

The 'dots' are a graphical indication of the quality of the demodulated signal. Small dots that are close together indicate a good signal. If the dots become spaced further apart, this indicates that the signal quality is degrading. This signal quality degradation can be caused by low Rx signal level due to, for example:

external interference

failure of any of the following: modem, receiver, far end transmitter, an antenna (either end), a feeder or connector (for example, due to water damage)

path issues such as multi-path fading or obstructions

To check the performance of the link using the constellation analyzer:

1.Select Link or Local or Remote > Performance > Constellation. A blank constellation diagram appears:

2.Click Start to start the constellation analyzer.

While the constellation analyzer is running, the terminal will temporarily stop collecting error performance statistics. If you want to run the constellation analyzer anyway, click OK when you see this warning message:

3.Click Stop to stop the constellation analyzer.

The terminal automatically resumes collecting error performance statistics.

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Viewing a summary of the link performance

To view the performance summary for a terminal:

Select Link or Local or Remote > Performance > Summary.

Field	Explanation
Link Performance
Correctable errors	The total number of correctable blocks since the last reset
Uncorrectable errors	The total number of uncorrectable blocks since the last reset
SNR (dB)	The Signal to Noise Ratio of the link in dB
RSSI (dBm)	The Received Signal Strength Indication at the Rx input in dBm
Errored seconds	The total number of operational seconds with errored traffic since the last
	reset
Error free seconds	The total number of error free operational seconds since the last reset
BER	The system will report an estimated Bit Error Rate up to a maximum of 1
	x 10-12
TX temperature	The measured temperature in the transmitter module in °C
RX temperature	The measured temperature in the receiver module in °C
Ethernet performance
Transmitted packets	The total number of transmitted Ethernet packets
Received packets	The total number of received Ethernet packets
Received packet errors	The total number of packets received with errors

If you want to reset the error counters, click Reset Counters.

Maintenance | 175

13. Maintenance

There are no user-serviceable components within the terminal.

All hardware maintenance must be completed by 4RF or an authorized service centre. Do not attempt to carry out repairs to any boards or parts.

Return all faulty terminals to 4RF or an authorized service centre.

For more information on maintenance and training, please contact Customer Services.

Caution: Electro Static Discharge (ESD) can damage or destroy the sensitive electrical components in the terminal.

Routine maintenance

Every six or twelve months, for both ends of the link, you should record the RSSI and SNR levels as well as checking the following:

Item	What to check or look for
Equipment shelter environment	Water leaks
	Room temperature
	Excessive vibration
	Vermin damage
Terminal mounting	Firmly mounted
Antenna cable connections	Tight and dry
Antenna cable and its supports	Not loose or suffering from ultra-violet degradation
Antenna and its mounting hardware	Not loose, rusty or damaged
Safety earth	Connections tight
	Cabling intact
DC system	Connections tight
	Voltage in normal limits
Batteries (if installed)	Connections tight
	Electrolyte levels normal